diff --git a/docs/data/data-grid/localization/data.json b/docs/data/data-grid/localization/data.json
index 4540c7ebb4f2d..2859d78553b48 100644
--- a/docs/data/data-grid/localization/data.json
+++ b/docs/data/data-grid/localization/data.json
@@ -19,7 +19,7 @@
     "languageTag": "bg-BG",
     "importName": "bgBG",
     "localeName": "Bulgarian",
-    "missingKeysCount": 8,
+    "missingKeysCount": 0,
     "totalKeysCount": 122,
     "githubLink": "https://github.com/mui/mui-x/blob/master/packages/x-data-grid/src/locales/bgBG.ts"
   },
diff --git a/packages/x-data-grid/src/locales/bgBG.ts b/packages/x-data-grid/src/locales/bgBG.ts
index 69f8a06b815cc..3c360f174e455 100644
--- a/packages/x-data-grid/src/locales/bgBG.ts
+++ b/packages/x-data-grid/src/locales/bgBG.ts
@@ -57,9 +57,9 @@ const bgBGGrid: Partial<GridLocaleText> = {
 
   // Filter operators text
   filterOperatorContains: 'съдържа',
-  // filterOperatorDoesNotContain: 'does not contain',
+  filterOperatorDoesNotContain: 'не съдържа',
   filterOperatorEquals: 'равно',
-  // filterOperatorDoesNotEqual: 'does not equal',
+  filterOperatorDoesNotEqual: 'не е равно',
   filterOperatorStartsWith: 'започва с',
   filterOperatorEndsWith: 'завършва с',
   filterOperatorIs: 'е',
@@ -80,9 +80,9 @@ const bgBGGrid: Partial<GridLocaleText> = {
 
   // Header filter operators text
   headerFilterOperatorContains: 'Съдържа',
-  // headerFilterOperatorDoesNotContain: 'Does not contain',
+  headerFilterOperatorDoesNotContain: 'Не съдържа',
   headerFilterOperatorEquals: 'Равнo',
-  // headerFilterOperatorDoesNotEqual: 'Does not equal',
+  headerFilterOperatorDoesNotEqual: 'Не е равно',
   headerFilterOperatorStartsWith: 'Започва с',
   headerFilterOperatorEndsWith: 'Завършва с',
   headerFilterOperatorIs: 'Равно е на',